Threaded members frequently become unusuable because of damage to the threads and/or the presence of foreign matter between the threads. Thread damage includes both physical damage to the thread profiles and damage to the surfaces of the threads. Thread profile damage can be caused when the threaded member is mis-threaded, cross-threaded, stripped, or otherwise abused; and surface damage can occur through long continued use of the threaded member which causes surface spalling of the threads. Foreign matter, such as corrosion, rust, paint, and the like, can be formed or introduced between the threads by leaving the threaded member unprotected from the environment or the source of foreign matter. In general, such threaded members can be reconditioned or restored by means of a thread reconditioning tool.
A wide variety of thread reconditioning tools are known, and they can generally be divided into threading dies, either one piece or multi-piece dies, and adjustable thread reconditioning tools. Single piece threading dies, which are primarily used to cut threads into unthreaded shafts, can also be used to recondition threads. Typically, the die is started at one end of the threaded member and rotated relative the threaded member until the cutting edges of the die restores the original thread profile, reforms the surface of the threads, and removes any foreign matter from between the threads. Multi-part threading dies, which generally have two diametrically opposite cutting die portions, are similar in operation to a single piece dies except that they can be assembled to the threaded member anywhere along the longitudinal axis of the member. Adjustable thread reconditioning tools generally include a guide surface, such as a curved or `V` shaped anvil against which the threaded member is placed, and a radially adjustable thread cutting means which is manually adjusted to engage the thread.
Each one of the known thread reconditioning tools is adequate to perform its intended function, but each possesses one or more drawbacks inherent in its design. For example, the single piece threading die must be started over the end of the theaded member. This is particularly disadvantageous when only the middle portion of a relatively long threaded member is damaged or when the end-most threads are damaged making it difficult to properly start the die. While multi-part dies can be assembled onto the threaded member at the desired longitudinal location, they require an adjusting step to position the die portions relative to one another and to the threaded member. Likewise, the adjustable thread reconditioning tools also require an adjustment step to locate the thread cutting means relative to the threaded member. The adjustment step required by multi-part dies and adjustable thread reconditioning tools requires that the tool user have a minimum level of skill to properly adjust the cutting means with respect to the thread to be reconditioned. For example, if the cutting means is loosely adjusted, the thread may not be reconditioned on the first attempt, thereby requiring repeated efforts to successfully recondition the thread. Moreover, if the cutting means is too tight, the final reconditioned thread may be smaller in diameter than acceptable.
Therefore, it is a broad overall object of the present invention, among others, to provide a new and improved thread reconditioning or restoring tool which overcomes the disadvantages of known thread reconditioning tools.
Accordingly, it is an object of the present invention to provide a thread reconditioning tool for reconditioning or restoring damaged threads and/or removing foreign matter from between threads on a threaded member which is simple in construction, has a minimum number of parts, is simple to operate, and inexpensive to manufacture.
It is another object of the present invention to provide a thread reconditioning tool which can be quickly placed over and located at a selected position along the longitudinal axis of a threaded member.
It is still another object of the present invention to provide a thread reconditioning tool which can be quickly and conveniently engaged and disengaged with the threads of an externally threaded member by a tool user having a minimum level of skill.
It is a further object of the present invention to provide a thread reconditioning tool which can be quickly and conveniently operatively engaged with threads of a threaded member without making any adjustments of the cutting means relative to the thread.